THERE’S no question about it, these past few wet years since the breaking of the drought in late 2019 has seen an explosion in the life cycle throughout nature and the whole ecosystem.
Deserts have bloomed and the life cycle of the plants and animals that live in these dry regions take advantage of the wetter times to quickly reproduce before their environment becomes dry again.
Shield shrimp eggs which have laid dormant on the top of Uluru spring into life with the first falls of rains on the rock.
Nature is remarkable and as the floods cause destruction and heart ache to those who live in these low-lying areas you cannot argue that it kicks starts a cycle to replenish what has been lost in the long droughts.
Nature has dealt with the native species since time began.
Now with our intervention with introducing many different plants and animals, nature is at work with these undesirable species to also reproduce and repopulate.
Large flows in our rivers have been a boon to fish travel along our big rivers where weirs and the like at low levels stop all fish migration.
Connectivity is vastly improved when these
blockages are flooded and fish can travel into the headwaters to spawn unless they come up against a large dam wall with no fish ladder to enable fish passage.
Unfortunately, the undesirable species of fish also make advantage of the long uninterrupted stretches of waterways to further spread their presence.
One vision that have been replayed on the nightly news shows the incredible numbers of European carp that have now dominated many of our rivers, vision of the beaches around the mouth of the Murray River being covered with millions of dead juvenile carp.
The carp numbers in the western rivers are now in plague proportions. We could have possibly argued that has been the case in years gone past where sampling of these rivers has shown carp make up the total of the biomass in the high ninety percent region.
Now with this boom of carp numbers we have seen farmers calling for the introduction of the carp virus as their crops are covered with dead carp after the flooding has receded.
Irrigators are also calling for the virus to be introduced as their foot valves on their pumps become choked with carp.
Vision of carp congregated below weirs and regulators show their numbers to be so high that it’s easy to scoop a landing net full of carp from the river with just one swipe!
We have come such a long way since those few
carp were liberated into our Australian waters. Carp are the masters of adaptation, surviving
long after our native species die of excessive water temperature, black water, drought conditions and as we are seeing now, they are the comeback kings, much to the detriment of our native species.
So, our fisheries managers and angling groups continue to stock our native fish and desirable species back into their native waters the carp and its other noxious neighbour, the European perch or redfin, as its mostly known by need no stocking to become the most dominant fish in our waterways.
While the carp are over taking the slow flowing western rivers of the Murray Darling, the redfin is starting to dominate in the upper reaches of our rivers.
Redfin are bad, yes, they are fantastic eating and can be great fun to catch but these fish are aggressive and can wipe out entire fisheries that they may make their way into be it by flood events of illegal stocking.
Where redfin have invaded the upper reaches where our threatened species such as the Macquarie perch exist, this generally means the Macquarie perch will soon be overcome by the European perch, the reddie.
The redfin has another tool in their arsenal of tools to dominate the rivers.
Redfin can carry Epizootic Haematopoietic Necrosis Virus and this virus has the potential to wipe out our native species as well as our desirable species.
The National Carp Control Plan has been released for the government to decide whether they will authorise the virus to be used to reduce the number of carp. https://www.agriculture.gov. au/…/national-carp-control.
If no action is taken in the short term, I believe we will become a nation that has the European carp and perch as our predominate fresh water species.
